There’s a piece of software I often use – Notepad++.
I enjoy it a lot.
Changing the CASE, duplicating lines, and all sorts of shortcuts, they’re useful.
I like it so much, I even added a Win + Key shortcut on my toolbar, so I can easy start it (it’s on my quick launch toolbar, from where I can launch stuff just by pressing Win + 1, Win + 2 etc.).
If you’re on Windows, try it out.